sparklyr: hof_aggregate – R documentation

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hof_aggregate

Apply Aggregate Function to Array Column

Description

Apply an element-wise aggregation function to an array column (this is essentially a dplyr wrapper for the aggregate(array<T>, A, function<A, T, A>[, function<A, R>]): R built-in Spark SQL functions)

Usage

hof_aggregate(
  x,
  start,
  merge,
  finish = NULL,
  expr = NULL,
  dest_col = NULL,
  ...
)

Arguments

`x`	The Spark data frame to run aggregation on
`start`	The starting value of the aggregation
`merge`	The aggregation function
`finish`	Optional param specifying a transformation to apply on the final value of the aggregation
`expr`	The array being aggregated, could be any SQL expression evaluating to an array (default: the last column of the Spark data frame)
`dest_col`	Column to store the aggregated result (default: expr)
`...`	Additional params to dplyr::mutate

Examples

## Not run: 

library(sparklyr)
sc <- spark_connect(master = "local")
# concatenates all numbers of each array in `array_column` and add parentheses
# around the resulting string
copy_to(sc, tibble::tibble(array_column = list(1:5, 21:25))) %>%
  hof_aggregate(
    start = "",
    merge = ~ CONCAT(.y, .x),
    finish = ~ CONCAT("(", .x, ")")
  )

## End(Not run)

sparklyr

R Interface to Apache Spark

v1.6.2

Apache License 2.0 | file LICENSE

Authors

Javier Luraschi [aut], Kevin Kuo [aut] (<https://orcid.org/0000-0001-7803-7901>), Kevin Ushey [aut], JJ Allaire [aut], Samuel Macedo [ctb], Hossein Falaki [aut], Lu Wang [aut], Andy Zhang [aut], Yitao Li [aut, cre] (<https://orcid.org/0000-0002-1261-905X>), Jozef Hajnala [ctb], Maciej Szymkiewicz [ctb] (<https://orcid.org/0000-0003-1469-9396>), Wil Davis [ctb], RStudio [cph], The Apache Software Foundation [aut, cph]

Initial release